The proposed research and training program, Predicting the Decline of Social Attention in Infants at Risk for Autism, will develop measures that detect decreases in attention to social phenomena among 6- to 18-month- old infants at high risk for developing an autism spectrum disorder (ASD). Measures of infant social attention will be administered to infants at high and low risk for ASD at 6, 9, 12, 15, and 18 months of age. Social attention will be evaluated behaviorally in three mother-infant-play interactions and using a standardized measure of infant social communication skills. Associations will be evaluated between behavioral measures of social attention and experimental measures involving eye tracking and electrophysiological measures of brain activity. The candidate will learn sophisticated newly developed methods of analyzing electrophysiological data that capitalize on the richness of longitudinal repeated-measures research design. The measurement focus of the study aims to improve accuracy and reduce the cost of early screening methods to create objective means of detection that can be applied in community clinical settings to improve the accessibility of means for identifying infants who would benefit from early ASD-related treatment. Brain-based markers of social attention will be evaluated as predictors of accumulated features of ASD evident in preliminary diagnostic testing when infants reach 18 months of age. Identifying biological markers of change in social attention, which has previously been associated with ASD onset, will greatly facilitate efforts to detect ASD during infancy and possibly even during the first year of life. The study offers several potential benefit to parents of infants at high risk for ASD and infants showing early signs of ASD. Our ability to detect warning signs of ASD during the first year will allow children to access treatment earlier than has been possible in the past. This research can help to pinpoint developmental domains that should be targeted for treatment during the infant and toddler stages of development. The development of effective early treatment strategies depends on identification of infants who will benefit from treatment based on rich and detailed characterization of social impairment prior to 12 months of age. Predicting the decline of social attention in 12-month olds is expected to improve developmental trajectories and skill attainment in infants demonstrating early features of ASD. In order to accomplish the research aims of this proposal, the applicant will pursue advanced training in (a) measurement and analysis of social interaction, social communication, and emerging language skills; and (b) acquisition and analysis of electrophysiological data from infants. This training and research experience will help the candidate achieve his career aims of improving early detection of ASD by linking measures of brain activity during the first and second years with the development of social attention during the same developmental time frame. The training plan incorporates sophisticated measurement methodologies that will be applied to linking patterns of change between brain activity and social behavior. Protected time to pursue these research and training aims will provide the applicant with skills and the opportunity to have a powerful impact on individuals at risk for ASD, individuals affected by ASD, and those who care for them. This research and training program directly address the elements of the NIMH strategic plan. Specifically, this project seeks (a) to identify behavioral and biological markers of mental disorder; (b) to use those markers to identify risk factors and protective factors for mental illness; and (c) to extend the reach of screening strategies into the community, to intervene earlier and more widely, and thereby to mitigate severity, disturbance, and cost of care for an increasingly prevalent mental disorder.